Toivonen, H.; Leppaenen, A.; Ylaetalo, S.; Lehtinen, J.; Hokkinen, J.; Tarvainen, M. et al. Finnish remote environmental monitoring field demonstration, article, October 1, 1997; (https://digital.library.unt.edu/ark:/67531/metadc692406/m1/1/: accessed December 18, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .